Our work on bacterial lipids has fortuntously led us to uncovering a new type of lipid in Streptococcus faecalis (faecium) ATCC 9790 which we have characterized as phosphatidyl diglucosyl diglyceride. Our initial studies have revealed it is biosynthesized by a novel type of reaction, transphosphatidylation, and that it functions on anchor by covalently binding lipoteichoic to the membrane. Our future studies will be mainly concerned with this phosphoglucolipid which is a primary antigen (in lipoteichoic acid form) and is an essential structural component of bacteria. We will study its synthesis in greater detail, its linkage to polyglycerophosphate teichoic acid, its degradation, its function as a substrate in the synthesis of lipoteichoic acid, and its occurrence as a lipoteichoic acid constituent in a variety of bacteria. We will also study the metabolism and function of a glucuronosyl diglyceride and a phosphatidyl monoglucosyl diglyceride in species of Pseudomonas.